The Computing Race to Space: From Sputnik to Apollo
By Dag Spicer, Senior Curator
The 1956 issue of Time magazine carried the story of 17-year-old Eagle Scout Jimmy Blackmon, a junior in high school who had spent the last three years building his own liquid-fueled rocket. At over six feet long and capable of reaching heights of thousands of feet, the launch of Blackmon’s rocket was forbidden by the Civil Aeronautics Administration when made aware of it. The rocket nonetheless made the news nationally and got Jimmy a one-on-one interview with German-American rocket scientist and public face of the us space program Dr. Wernher von Braun.¹ He also did manage to launch a (much safer) solid-fuel version of rocket, discretely, on the North Carolina waterfront later that year.
Blackmon became an actual rocket scientist, graduating with a PhD in mechanical and aerospace engineering from UCLA in 1972 and teaching for 40 years at the University of Alabama in Huntsville. His path from boyhood onward is symbolic of the aspirations and challenges of the Space Race and how it entrained an entire nation on a project of mass science and technology development and education. Since the announcement of the Truman Doctrine and the institution of the Marshall Plan in 1947, the nation was at war with the Soviet Union — a Cold War — and one of the new battle-fields was space.
Blackmon’s rocket coincided with the launch of the Soviet’s Sputnik satellite that same year. The successful launch of Sptunik represented what many feared could become “a technological Pearl Harbor.”² Technology and science became the weapons of choice in this new contest: it was not just the number of missiles a nation possessed that mattered, it was also the number of scientists and engineers. The moral panic resulting from a feared “knowledge gap” between Russian and American schoolchildren fostered massive government investments in programs (at both state and federal levels) to update science education across the country. Engineers, in particular, were portrayed as modern heroes, applying their specialized knowledge for both the protection of the United States and its allies as well as for the benefit of humanity.
It was also at the time of Sputnik when electronic digital computers began to be used in earnest by an ever-widening circle of users. In the late 1950s, computer systems were usually room-size mainframe systems, costing millions of dollars to purchase and operate. By the mid-1950s the industry had bifurcated from “number crunchers” into scientific and business users. Scientific customers needed high-speed binary floating-point capability and would typically use the FORTRAN programming language; business users opted for decimal-oriented computers optimized for dealing with financial or text information. These enormous devices could be rented to save money but even then, to have access to an electronic computer put one at the very forefront of science. The new space program would make ample use of this technology.
It’s no coincidence that the former National Advisory Committee for Aeronautics (NACA) was renamed the National Air and Space Administration (NASA) the year after Sputnik. NASA’s new role was to help reorient the nation’s scientific and industrial resources to the space program. In the words of nasa Director Hugh Dryden:
“It is of great urgency and importance to our country both from consideration of our prestige as a nation as well as military necessity that this challenge [Sputnik] be met by an energetic program of research and development for the conquest of space…It is accordingly proposed that the scientific research be the responsibility of a national civilian agency…”³
As an institution that performed a lot of routine calculations, NASA was an early and enthusiastic adopter of electronic computers, both digital as well as their earlier analog counterparts, some of which were still very useful in conducting simulations. By the time of the Apollo program’s first flight in 1966, nearly all aspects of the mission were under control or supervision of computers: mission planning, rocket countdown and launch, guidance, navigation, control of the spacecraft itself, telemetry and tracking, touchdown on the Moon, and return to Earth. Apollo built on the success of two prior us rocket programs: Mercury, which sent single astronauts into orbit around Earth; and Gemini, which sent two astronauts together into orbit to understand how space-flight affects humans, how to do a spacewalk, and how to connect two spacecraft together. All of these steps in the Mercury and Gemini programs were geared toward providing technologies and procedures for Apollo.
The planned Apollo mission relied on computers of all sizes and types: from large scientific mainframes, like the IBM 7090/7094, to legions of smaller computers, like the IBM 1401 series, and even early single-user computers, like the Librascope LGP-30 and the Bendix G-15. At its peak, the program had over 400,000 employees and contractors, each dedicated to a specific mission or task. Mission-critical calculations depended on great coordination between departments, employees, companies, and machines. Naturally, all the computers were Earth-bound; it would take a special effort to bring computing to the spacecraft themselves.
There were two main computing systems used on-board the Apollo spacecraft. The first was the Apollo Guidance Computer (AGC), originally a room-size set of seven-foot-high racks filled with electronics, which was eventually compressed into a single 70-pound box and controlled through an operator panel known as the Display Keyboard (DSKY). The AGC was a remarkable development for several reasons: 1) it compressed the AGC circuitry by hundreds of times using the then new technology of integrated circuits (ICs); and 2) its software was “man-rated,” meaning it was reliable enough to be used in a real mission with living people, a first for computer science. Built by Raytheon, the AGC was one of the earliest and largest users of ICs, providing real-time guidance and control to the spacecraft (both the lunar module and the command and service module had an AGC), a virtual electronic lifeline to the astronauts.⁴
The second computer receives far less attention. Known as the instrument unit (IU), this computer-controlled system was physically arrayed around the circumference of the Saturn v rocket launch vehicle’s third stage. The IU provided the guidance and stage sequencing system for the rocket and was designed by NASA and IBM. It comprised multiple sensors such as accelerometers, gyros, pressure and temperature sensors, and a radar tracking and command radio system, among other capabilities. Parts of the IU were actually based on the Nazi V-2 rockets of wwii. The main computer in the IU was the Launch Vehicle Digital Computer (LVDC) designed and built by IBM’s Electronic Systems Center in Owego, New York. Simple by today’s standards, the LVDC was the “autopilot” for the Apollo rocket from launch to Earth orbit insertion. While the LVDC and AGC ran at only a couple of megahertz in terms of clock speed, it was the outstanding reliability of the systems that made them the right choice. Similarly, the multiyear development cycles of such projects, sometimes a decade or more in duration, usually prevent the most recent technologies from being chosen for a mission in the future.
The Space Race, roughly 1957 to 1977, was one of the great dramas of the 20th century. Like World War II before it, the contest’s two adversaries deployed national programs of scientific and technical development in a trial of competing political systems and, ultimately, ways of life. Despite this somber backdrop, the era of Apollo was a time of immense excitement and optimism — on both sides of the Iron Curtain. Space seemed limitless and became the chess board on which a new battle of wills and ideologies was played out, one in which the combatants were not soldiers but engineers. The computer was at the side of these modern day Prometheans every step of the way to the Moon and back.
Notes
- Von Braun was the leading German rocket scientist brought to the United States at the end of World War II as part of Operation Paperclip, an American effort to prevent German scientists from falling into Soviet hands. As Soviet and American armies marched quickly toward Berlin in the final days of the war, German scientists fled to one of the two approaching armies. The success of both the American and Soviet rocket programs would not have been possible without this cohort of fleeing German rocket scientists.
- James Buckley, “A Technological Pearl Harbor,” New York Times, July 23, 1971, https://www.nytimes.com/1971/07/23/archives/a-technological-pearl-harbor.html.
- “A National Research Program for Space Technology,” a staff study of the NACA, January 14, 1958.
- ICs were very expensive at the start of the program — about $1,000 each — whereas by 1964, they had dropped to about $25 each, as chip manufacturers improved their production processes and yields, driving costs lower.
About the Author
Dag Spicer leads the Museum’s collection strategy and supports multiple projects and initiatives across the institution, including those in research, education, fundraising, public programs, and marketing. He is the longest-serving employee at the Museum, having started in 1996, and holds degrees in history, electrical engineering, and the history of science and technology.
“The Computing Race to Space: From Sputnik to Apollo” is published in the Computer History Museum’s 2019 issue of Core magazine.
